Intrathecal immunoglobulin synthesis has been observed in various neurological disorders, such as Multiple Sclerosis1.
The traditional approach for the evaluation of intrathecal immunoglobulin synthesis is detection of CSF-restricted oligoclonal IgG bands (OCB)2.
OCB is a specialised gel-based technique that requires highly skilled operators to interpret.
Even when experienced professionals interpret the results, inter-laboratory and inter-observer variability can be observed3.
“[…] one of the clear advantages of кFLC is the reliable and rater-independent determination, which should overcome technical difficulties and finally allow a widespread use.”
Hegen, Multiple Sclerosis 20224
The Freelite Mx Kappa assay measures Kappa Free Light Chain (FLC) concentration in CSF, run on the Optilite® automated analyser.
CSF Kappa FLC measurement is recognised as interchangeable with OCB when used as an aid in the diagnosis of Multiple Sclerosis5.
The laboratory process for evaluating intrathecal immunoglobulin synthesis can be simplified by the use of Freelite Mx assays run on the Optilite analyser.
Intrathecal synthesis of immunoglobulins is a hallmark of Multiple Sclerosis2. An elevated Kappa Free Light Chain (FLC) concentration in CSF indicates intrathecal immunoglobulin synthesis3.
An impaired blood-CSF barrier can also cause Kappa FLC to appear in CSF, so the origin of CSF Kappa FLCs needs to be identified4.
Calculations that involve CSF/serum Kappa FLC and CSF/serum albumin quotients, such as Kappa Index, help differentiate whether the Kappa FLCs have been intrathecally synthesized or are derived from serum3.
In cases where CSF albumin is also elevated, increases in CSF Kappa FLC are unlikely to be due to intrathecal synthesis, as increased CSF albumin indicates an impaired blood-brain barrier3.
There is a good overall agreement between Kappa Index results and the absolute CSF Kappa FLC level. However, Kappa Index appears superior in cases of low or modest intrathecal production of Kappa FLCs3.
Generate results to calculate CSF/Serum ratios, using assays designed to measure both CSF and serum samples using a single instrument.